add button

GUI/View/Sample/SampleForm.cpp

@@ -44,11 +44,17 @@ public:
     {
         auto* l = new QHBoxLayout(this);
         l->setContentsMargins(0, 0, 0, 0);
-        auto* layer_btn = new QPushButton("Add layer", this);
         l->addStretch();
+
+        auto* layer_btn = new QPushButton("Add layer", this);
         l->addWidget(layer_btn);
-        l->addStretch();
         connect(layer_btn, &QPushButton::clicked, [=] { ec->addLayerItem(layer); });
+
+        auto* stack_btn = new QPushButton("Add stack", this);
+        l->addWidget(stack_btn);
+        connect(stack_btn, &QPushButton::clicked, [=] { ec->addLayerItem(layer); });
+
+        l->addStretch();
     }
 
     LayerItem* m_layer;